Tuner won't tune car cause of Po103 ?
06-05-2008, 08:45 PM
#1
Tuner won't tune car cause of Po103 ? I took my car to get tuned today, which is a stock 98' Procharged LS1 Camaro at 7-8#.
Previously, he tried to tune it but stated that I had a vacumn leak. This was causing the idle to fluctuate or roll and showed a lean A/F mixture and also the long term fuel trim was maxed out. He pointed out that we had an LS6 intake with the LS1 coolant pipes still installed. So we took them off and installed the LS6 coolant lines and new intake seals for fear that this was causing a vacumn leak. We still had an issue with the idle fluctuating even after we checked everywhere for vacumn leaks. I will note though, that the idle did improve a little. Still, he would not put the car on the dyno because he said the computer was not able to go into a closed loop and let the sensors control the engine. To compensate for this, he set the fuel mixture on the rich side. The vacumn reading was 17-20”,which increased to 20-22” after the intake was removed.
We brought it back to the tuner even though we still had an SES light, but we figure that it was still popping up due to the lack of a complete tune while only under full throttle. The trouble code is a PO103, which is the MAF reading a higher than expected voltage or airflow. At the same time my A/F was reading 16:1. Now I have read that this can cause the A/F to lean out. I cleaned it with MAF cleaner and still no better, so we got the idea to disconnect the MAF and suddenly the car idled perfect and the A/F dropped to 14.7:1 !!! What is the problem? Is my MAF bad or could I still have a vacumn leak? I do have a de-screened MAF, could this cause it?
Previously, he tried to tune it but stated that I had a vacumn leak. This was causing the idle to fluctuate or roll and showed a lean A/F mixture and also the long term fuel trim was maxed out. He pointed out that we had an LS6 intake with the LS1 coolant pipes still installed. So we took them off and installed the LS6 coolant lines and new intake seals for fear that this was causing a vacumn leak. We still had an issue with the idle fluctuating even after we checked everywhere for vacumn leaks. I will note though, that the idle did improve a little. Still, he would not put the car on the dyno because he said the computer was not able to go into a closed loop and let the sensors control the engine. To compensate for this, he set the fuel mixture on the rich side. The vacumn reading was 17-20”,which increased to 20-22” after the intake was removed.
We brought it back to the tuner even though we still had an SES light, but we figure that it was still popping up due to the lack of a complete tune while only under full throttle. The trouble code is a PO103, which is the MAF reading a higher than expected voltage or airflow. At the same time my A/F was reading 16:1. Now I have read that this can cause the A/F to lean out. I cleaned it with MAF cleaner and still no better, so we got the idea to disconnect the MAF and suddenly the car idled perfect and the A/F dropped to 14.7:1 !!! What is the problem? Is my MAF bad or could I still have a vacumn leak? I do have a de-screened MAF, could this cause it?
06-05-2008, 08:50 PM
#2
Take a 3' piece of 5/16th or similar hose & put one end in your ear (like a stethascope) and place the other end around the back of the intake first to listem for a vac "hiss" arond the vac fittings. Then move to each injector bottom & listen all around it. A hiss indicates a bad O-ring. Vac leaks cause all sorts of tuning issues.
Good Luck!
Good Luck!
06-05-2008, 09:09 PM
#5
Take a 3' piece of 5/16th or similar hose & put one end in your ear (like a stethascope) and place the other end around the back of the intake first to listem for a vac "hiss" arond the vac fittings. Then move to each injector bottom & listen all around it. A hiss indicates a bad O-ring. Vac leaks cause all sorts of tuning issues.
Good Luck!
Good Luck!
06-05-2008, 09:47 PM
#6
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well the code is MAF or VAF A circuit high input so that said id look at the MAF and maybe clean it with TB cleaner and chech the clamps by the MAF and elsewhere on the intake
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06-05-2008, 10:09 PM
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do this start the car let it idle down and get a steady idle the go and unplug the MAF if the car suddenly changes tone dies or sounds completey different its not the MAF if it stays the same then the car is in limp mode and most likely you need a new map because its running of off a preset setting from the factory tune
06-05-2008, 10:14 PM
#9
do this start the car let it idle down and get a steady idle the go and unplug the MAF if the car suddenly changes tone dies or sounds completey different its not the MAF if it stays the same then the car is in limp mode and most likely you need a new map because its running of off a preset setting from the factory tune
So by this, you are saying that I need a new MAP sensor?
06-05-2008, 10:16 PM
#10
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replace the MAF and ull be good to go the car is getting a shitty reading from the MAF and running like **** when you unplug it the car reads a preset setting and it clears it out when it stops taking the input from the MAF and is uses the MAP and limp mode setting to clear it up
06-05-2008, 10:19 PM
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if the MAP was the issues ud get s MAP input circuit high not MAS and ud have the same issues just viseversa that was my issue i had the same code and i didnt the same thing unplugged the MAS and it cleared up replaced it with a stock GM one never had an issue
06-05-2008, 10:21 PM
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do this start the car let it idle down and get a steady idle the go and unplug the MAF if the car suddenly changes tone dies or sounds completey different its not the MAF if it stays the same then the car is in limp mode and most likely you need a new map because its running of off a preset setting from the factory tune
